Van der Waals-Zeeman Colloquium

Tuesday, 16 November 2010, 16:00 (Science Park 904)

Theory and computer simulation of complex fluids

Dr. Fathollah Varnik
Interdisciplinary Centre for Advanced Materials Simulation (ICAMS) Ruhr University Bochum, Germany

In this talk, I will provide an overview of our research activities in the field of theory and simulation of complex fluids and show, via specific examples, how the lattice Boltzmann (LB) method can be tuned to study phenomena as various as stability and dynamics of droplets on patterned substrates and collective behavior of suspensions of red blood cells under shear flow. While in these studies thermal fluctuations are ignored, they might be important in other cases such as colloidal dispersions and nano-droplets. For a study of this latter issue, we have recently proposed a theory in order to include thermal noise in lattice Boltzmann models for non-ideal fluids. We present main ideas of this theory and a test thereof in the case of spreading dynamics of nano-droplets on flat substrates. It is found that the well-known Tanner's law (which states that the droplet's base radius scales as R~t1/10) is replaced by a faster spreading, R~t1/6. This result is in agreement with previous works using scaling analysis of a stochastic lubrication equation. Last but not least, I will also present results of our recent molecular dynamics studies on hard sphere glasses under shear with a particular focus on shear localization.